Subtle but detectable changes in background sound levels about a spacecraft may offer a new technique for preventing a catastrophic air leak.

The risk of collision between the continuously staffed International Space Station and manmade orbital debris or difficult to detect micrometeoroids is a constant concern.

Former ISS commander Chris Hadfield installs sound sensor/recorder in U. S. Destiny lab as part of work on new leak detection system. Photo Credit: NASA

A leak aboard the space station would sound an alarm, warning astronauts to head for their two Soyuz crew transports and possible escape to Earth. Or, if they had the time and wherewithal, the astronauts could attempt to quickly close off a leaking module to prevent the need to abandon the station.

However, pinpointing the source of a breach behind the equipment racks that cover much of the inner hull of the six-person orbiting science lab could take some time-consuming detective work by astronauts faced with a crisis.

The Ultrasonic Noise Background Test, led by Eric Madaras, a NASA Langley Research Center aerospace technologist, may offer an alternative.

"If a leak does occur, it's one of those things where you may not have a lot of time," said Madaras in a NASA statement describing the tech project. "These guys can always go sit in the Soyuz capsule and close the door and go home. They've got that capability. But no one wants to just abandon ship, so there's always this desire to deal with it."

As part of the UNBT, ISS astronauts are installing 14 distributed impact detection system (DIDS) sensor/recorders on the internal pressure walls of the station's U. S. segment Destiny laboratory and Tranquility module.

DIDS units are high-speed, four-channel digitizers tuned to record the ultrasonic background noise of the hull. Each sensor/recorder has four pressure-sensitive transducers. Madaras compares them to the pickup coils on an electric guitar.

If they are successful at characterizing the background noise, the Langley researchers could then modify their hardware to pick out the sounds associated with an actual leak, giving future spacecraft crews help in locating a breach in time to apply a patch.